In the field of pipe liners and lining methods, a need exists for the reduction or control of the contamination of the ambient, that is caused by the liners or lining methods used. This is particularly true in the field of sewer pipes, since these carrier pipes are numerous and they are located in places of high population density where contamination has been a problem. Moreover, large numbers of these pipes cannot be dug up, or it is impractical or expensive to do so, and because many of these pipes need relining in order to prevent danger to these sewage treatment plants connected thereto.
Styrene is one of the dangerous contaminants present in the liners and lining methods used heretofore. For example, in the liner and lining method described in Wood U.S. Pat. No. 4,009,063, the lining is totally impregnated with resins containing styrene, and this or other contaminants have been released to the atmosphere during the lining process. In some cases gaseous styrene was released from the impregnated liner because hot air or steam was circulated through the liner during the curing process, and no effective provision or steps were made to prevent the release of the styrene from the hot air or steam in cases where the styrene was volatilized or stripped out of the resin by the hot air or steam. In other cases, the liner itself was porous or perforated, either on purpose or by accident during the insertion or curing of the liner in a sewer pipe, and this perforation was on the outside of the liner.